diff --git a/configs/Kconfig b/configs/Kconfig
index 17e9fdbd318..c4565dbe7d5 100644
--- a/configs/Kconfig
+++ b/configs/Kconfig
@@ -858,8 +858,18 @@ config ARCH_BOARD_CUSTOM
 
 endchoice
 
+config ARCH_BOARD_CUSTOM_DIR
+	string "Custom board directory"
+	depends on ARCH_BOARD_CUSTOM
+	---help---
+		If the custom board configuration is selected, then it is necessary
+		to also tell the build system where it can find the board directory
+		for the custom board. This may be either a relative path from the
+		toplevel NuttX directory (like "configs/myboard") or an absolute path
+		to some location outside of the NuttX source tree (like
+		"~/projects/myboard").
+
 config ARCH_BOARD
-	string
 	default "amber"               if ARCH_BOARD_AMBER
 	default "arduino-due"         if ARCH_BOARD_ARDUINO_DUE
 	default "avr32dev1"           if ARCH_BOARD_AVR32DEV1
@@ -946,7 +956,6 @@ config ARCH_BOARD
 	default "zp214xpa"            if ARCH_BOARD_ZP214XPA
 	default "zkit-arm-1769"       if ARCH_BOARD_ZKITARM
 	default "sim"                 if ARCH_BOARD_SIM
-	default ""                    if ARCH_BOARD_CUSTOM
 
 comment "Common Board Options"